1. Field
The present disclosure relates generally to tools for forming aircraft parts and, in particular, to inflatable bladders. More particularly, the present disclosure relates to a method and apparatus for a reinforced bladder.
2. Background
Aircraft generally include an airframe, which may be regarded as an underlying skeleton to which skins are attached to form a smooth aerodynamic outer surface. The wings also include an underlying structure covered with skins. Typically, skins are light and thin to minimize the weight of the aircraft and increase its payload and range. Since skins are thin, they are generally flexible and require stiffening to prevent undesired movement, flexing, and vibration during flight.
Stringers of various shapes may be used for stiffening fuselage sections and wing skins on aircraft. These stringers may have acute angles that result in an I shape, J shape, trapezoidal shape, rectangular shape, semi-circular shape, or some other suitable shape.
Aircraft are being designed and manufactured with greater and greater percentages of composite materials. Composite materials are used in aircraft to decrease the weight of the aircraft. This decreased weight improves performance features such as payload capacity and fuel efficiency. Further, composite materials provide longer service life for various components in an aircraft.
Composite materials may be tough, light-weight materials created by combining two or more functional components. For example, a composite material may include reinforcing fibers bound in a polymer resin matrix. The fibers may be unidirectional or may take the form of a woven cloth or fabric. The fibers and resins may be arranged and cured to form a composite structure.
Composite stringers may be attached to a composite skin using fasteners, curing the composite stringers to the composite skin, or by other desirable methods. When composite stringers are cured directly to a composite skin, pressure may be applied to the composite stringers. Pressure may be applied using at least one of tooling external to the composite stringers or tooling within the composite stringers. Applying pressure unevenly may cause manufacturing inconsistencies such as voids, wrinkles, resin richness, and other inconsistencies.
Following curing, removing tooling from within the composite stringers may reduce the weight of the resulting aircraft. Further, following curing, failing to remove tooling from within the composite stringers may undesirably affect performance. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.